<?php

echo "Hello World!\n";
$v = 100;
echo "</br>";
echo "\n";
// $v++;
$v--;
echo $v;

?>
<!-- <?= $_SERVER['HTTP_USER_AGENT'] ?> -->
<div></div>
<?php
$ages = array("Alice" => 25, "Bob" => 30);
echo $ages["Alice"]; // 输出 25
?>